1. Technical Field
The present invention relates to test apparatus and a test method.
2. Related Art
A known semiconductor test apparatus measures the width (referred to hereinafter as “data width”) of an eye aperture (referred to hereinafter as the “data window”) of a response signal, which is output by a device under test in response to a test signal. This semiconductor test apparatus judges the acceptability of the device under test based on whether the data width is within a prescribed range.
The semiconductor test apparatus generates a strobe signal used to measure the data width, and detects leading edges and trailing edges of the response signal based on the strobe signal, as described in, for example, WO 2007/091413. The data width can be measured as the difference between a leading edge and a trailing edge of the response signal.
In conventional data width detecting methods, however, the leading edges and trailing edges of the response signal are detected in different test cycles, and therefore the data width of the response signal cannot be efficiently detected. This problem has become especially prominent recently due to an increase in the number of pins in a device under test.